Fluorogenic 1,3-dipolar cycloaddition within the hydrophobic core of a shell cross-linked nanoparticle

Area of Science:

• Polymer Chemistry
• Nanotechnology
• Materials Science

Background:

• Block copolymers are versatile macromolecules with applications in nanotechnology.
• Functionalization of polymers is key to creating advanced materials.
• Acetylene groups offer unique reactivity for further chemical modification.

Purpose of the Study:

• To synthesize novel acetylene-functionalized block copolymers.
• To develop a method for creating shell cross-linked (SCK) nanoparticles with acetylene groups in the core.
• To demonstrate the utility of the incorporated acetylene groups for fluorescent labeling.

Main Methods:

• Synthesis of block copolymers using nitroxide mediated polymerization (NMP) and reversible addition fragmentation transfer (RAFT) techniques.
• Self-assembly of acetylene-functionalized block copolymers into micelles.
• Cross-linking of micelles to form shell cross-linked knedel-like (SCK) nanoparticles.
• Characterization using dynamic light scattering (DLS), atomic force microscopy (AFM), and transmission electron microscopy (TEM).
• Copper(I)-catalyzed 1,3-dipolar cycloaddition reaction for fluorescent labeling.

Main Results:

• Novel block copolymers with terminal acetylenes and narrow polydispersities were successfully synthesized.
• Acetylene-functionalized amphiphilic block copolymers were converted into SCK nanoparticles with acetylene groups in the core.
• Dynamic light scattering, AFM, and TEM confirmed the formation and dimensions of micelles and nanoparticles.
• The Click functionality within the nanoparticle core was confirmed by fluorogenic cycloaddition, yielding intensely fluorescent nanoparticles.

Conclusions:

• The study successfully developed acetylene-functionalized amphiphilic block copolymers.
• These copolymers can be self-assembled and cross-linked into SCK nanoparticles with accessible core functionality.
• The incorporation of acetylene groups enables straightforward fluorescent labeling of the nanoparticle core via Click chemistry, paving the way for advanced functional nanomaterials.